Forty-seven Afghan asylum seekers were arrested by police in Sukabumi, West Java, on Sunday as they allegedly attempted to sail to Australia’s Christmas Island, police told the Antara news agency.

“We caught the 47 illegal immigrants as they were trying to cross to Australia,” Adj. Comr. Sumaryoto, head of the Ciemas subdistrict police, told Antara. “They had been transported by two medium trucks from Cisarua in Bogor.”

The asylum seekers had been tailed by police since Bagbagan, near the coastal town of Pelabuhan Ratu, as they headed to Ciemas, Sumaryoto said. Some of the men allegedly tried to flee when police pulled the trucks over near Girimukti village. All have been held at the Ciemas subdistrict police station as the investigation continues.

“We are still investigating this sending of illegal immigrants to Sukabumi’s waters,” Sumaryoto said according to Antara.

The coast around Ciemas is popular with smugglers because of its close proximity to Christmas Island. Asylum seekers, mostly from Afghanistan and Iran, brave the treacherous 236 mile journey to Christmas Island with the hopes of gaining refugee status in Australia. Many are detained in Indonesia, a popular stepping stone for Asian asylum seekers attempting to cross to Australia.

Local police say they have been increasing patrols of the area, relying on tips from local residents.

“We have also been coordinating with local fishermen,” Sumaryoto said. “In the past, arrests were the result of reports from local residents who suspected groups of foreigners staying near the beach.”